WikiSpam means unwanted content, usually links for advertizing casino or porn sites, that is posted by unknown people. These are usually paid workers from professional spamming organizations in underdeveloped countries who blindly post that content.
A good StartingPoint for information about WikiSpam is at MeatBall:WikiSpam. The MeatBall hast SunirShah is a top spam expert, who held the excellent wiki spam workshop at the WikiSym 2005 in San Diego.
You can find some diskussion about the spam defense features of ProWiki at FeatureRequests/SpamDefense.
- info: unwanted advertizing - usually to casino or porn sites - posted to wikis.